CN104203835A - Functionalization of graphene holes for deionization - Google Patents

Abstract

The invention relates to a method for deionization of a solution. The method comprises functionalizing plural apertures of a graphene sheet to repel first ions in the solution from transiting through the functionalized plural apertures. The non-transiting first ions influence second ions in the solution to not transit through the functionalized plural apertures. The graphene sheet is positioned between a solution flow path input and a solution flow path output. Solution enters the solution flow path input and through the functionalized plural apertures of the graphene sheet, resulting in a deionized solution on the solution flow path output side of the graphene sheet and a second solution containing the first ions and second ions on the solution flow path input side of the graphene sheet.

Description

Functionalization of graphene pores for deionization

field of invention

The present invention relates to ion filtration, and more particularly to methods and systems for deionization utilizing the functionalization of graphene pores.

Background of the invention

As fresh water sources become increasingly scarce, many countries are looking for solutions that can convert salt water, most notably sea water, into clean drinking water.

Existing technologies for water desalination fall into four broad categories, namely, distillation, ionic processes, membrane processes, and crystallization. The most efficient and commonly used of these techniques are Multi-Stage Flash Distillation (MSF), Multiple Effect Evaporation (MEE) and Reverse Osmosis (RO). Cost is the driving factor for all of these processes, where both energy and capital costs are significant. Thoroughly developed RO and MSF/MEE technologies. Currently, optimal desalination schemes require 2 to 4 times the theoretical minimum energy limit established by simple evaporation of water and is 3 kJ/kg to 7 kJ/kg. Distillative desalination methods include multi-stage flash distillation, multiple-effect distillation, vapor compression, solar humidification and geothermal desalination. These approaches share a common pathway of changing the state of water for desalination. These approaches use heat transfer and/or vacuum pressure to evaporate the saline solution. Then, the water vapor is condensed and collected as fresh water.

Ionic process desalination methods focus on chemical and electrical interactions with ions in solution. Examples of ionic process desalination methods include ion exchange, electrodialysis, and capacitive deionization. Ion exchange introduces solid polymer ion exchangers or mineral ion exchangers into the brine solution. Ion exchangers bind desired ions in solution so that they can be easily filtered out. Electrodialysis is a process that uses cation- and anion-selective membranes and voltage potentials to create alternating passages of fresh water and saline solutions. Capacitive deionization uses a voltage potential to remove charged ions from solution, trap the ions and simultaneously pass water molecules.

Membrane desalination processes use filtration and pressure to remove ions from solutions. Reverse osmosis (RO) is a widely used desalination technique that applies pressure to a brine solution to overcome the osmotic pressure of the ionic solution. The pressure pushes water molecules through the porous membrane into the freshwater compartment while trapping ions, creating a highly concentrated brine solution. Pressure is the driving cost factor for these methods because pressure is required to overcome osmotic pressure to capture fresh water. Crystallization desalination is based on the phenomenon of preferential formation of crystals that do not contain ions. Pure water can be separated from dissolved ions by generating water of crystallization in the form of ice or methyl hydrate. In the case of simple freezing, water is cooled below its freezing point, thereby producing ice. Then, the ice is melted to form pure water. The methanol crystallization process uses methane gas to filter a salty aqueous solution to form methane hydrate, which occurs at a lower temperature than water freezing. Methanol rises, facilitating the separation, and then heats up to break down into methane and desalinated water. The desalinated water is collected and methane is reused.

Evaporation and condensation for desalination are generally considered energy efficient but still require a concentrated heat source. When done on a large scale, evaporation and condensation for desalination are often co-located with power plants and are subject to geographic distribution and size constraints.

Capacitive deionization is not widely used, probably because capacitive electrodes tend to become fouled with removed salts and require frequent maintenance. The necessary voltage tends to depend on the spacing of the plates and the flow rate, and this voltage can be a hazard.

Reverse osmosis (RO) filters are widely used for water purification. RO filters use porous or semi-permeable membranes, usually made of cellulose acetate or polyimide membrane composites and typically have a thickness of 1 millimeter (mm). These materials are hydrophilic. Membranes are usually helically wound into a tubular form for ease of handling and membrane support. The membrane exhibits a randomly sized pore size distribution, with the largest sized pores being small enough to allow water molecules to pass through and not to allow or block the passage of ions such as salts dissolved in water. Although a typical RO membrane has a thickness of 1 millimeter, the inherently random structure of RO membranes defines long and circuitous or tortuous paths for water flowing through the membrane, and these paths can be much greater than 1 millimeter in length. The length and random configuration of the pathways require considerable pressure to strip the water molecules from the ions at the surface and then move the water molecules through the membrane against osmotic pressure. As such, RO filters tend to be energy inefficient.

FIG. 1 is an abstract illustration of a cross-section of an RO membrane 10 . In FIG. 1 , membrane 10 defines an upstream surface 12 facing an upstream aqueous ionic solution 16 and a downstream surface 14 . The ions exemplified on the upstream side are selected as +-charged sodium (Na) and --charged chlorine (Cl). Sodium is exemplified as being associated with 4 water molecules ( _H2O ) that solvate the ion. Each water molecule includes 1 oxygen atom and 2 hydrogen (H) atoms. One of the paths 20 for water flow in the RO membrane 10 of FIG. 1 is illustrated as extending from pores 20u on the upstream surface 12 to pores 20d on the downstream surface 14 . Path 20 is illustrated as convoluted, and it is not possible to show the true tortuous nature of typical paths. Furthermore, it may be desirable for the path illustrated as 20 to connect with multiple upstream apertures and multiple downstream apertures. The path 20 through the RO membrane 10 may not only be coiled, but it may also vary over time as some pores become clogged with unavoidable debris.

Alternative water desalination methods and devices are desired.

Summary of the invention

A method of deionizing a solution is disclosed, the method comprising the step of functionalizing a plurality of pores of a graphene sheet to repel first ions in the solution from being transported through the functionalized plurality of pores. porosity, non-transported first ions affect second ions in the solution from being transported through the functionalized plurality of pores; placing the graphene sheet at the solution flow path input and solution flow path between the output ends; and allowing solution to enter the solution flow path input end and pass through the functionalized plurality of pores of the graphene sheet, thereby creating a depletion on the solution flow path output side of the graphene sheet The ionized solution and a second solution comprising first ions and second ions on the input side of the solution flow path of the graphene sheet.

In embodiments, the first ion may be a negatively charged ion, the second ion may be a positively charged ion, and functionalizing the plurality of pores may include functionalizing the perimeters of the plurality of pores to has a negative charge, thereby repelling negatively charged ions in the solution. Functionalizing the edges of the plurality of pores to have a negative charge may include functionalizing the edges with oxygen, nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, or iodine. Alternatively, functionalizing the edges of the plurality of pores to have a negative charge may comprise functionalizing the edges with polymer chains or amino acid chains having an overall negative charge. In another embodiment, the first ions may be positively charged ions, the second ions may be negatively charged ions, and functionalizing the plurality of pores may include functionalizing the edges of the plurality of pores to have positively charged, thus repelling the positively charged ions in the solution. Functionalizing the edges of the plurality of pores to have a positive charge may include functionalizing the edges with boron, hydrogen, lithium, magnesium, or aluminum. Alternatively, functionalizing the edges of the plurality of pores to have a positive charge may comprise functionalizing the edges with polymer chains or amino acid chains having an overall positive charge.

The method for deionization may further include sizing the plurality of pores of the graphene sheet to resist transport of the first ions. The method may further include applying a charge to the graphene sheet, wherein the charge repels the first ion.

A method of deionizing a solution is disclosed, the method comprising the step of: functionalizing a first plurality of pores of a first graphene sheet to repel first ions in the solution from being transported through the functionalized The non-transported first ions also affect the second ions in the solution from being transported through the functionalized first plurality of pores; making the second graphene sheet the first plurality of pores Two plurality of pores functionalized to repel second ions in the solution from transport through the functionalized second plurality of pores, the non-transported second ions also affecting the first ions in the solution not transporting through the functionalized second plurality of pores; placing the first graphene sheet downstream of the solution flow path input and placing the second graphene sheet at the first graphene between the sheet and the solution flow path output; and allowing solution to enter the solution flow path input, pass through the first graphene sheet, and then pass through the second graphene sheet, thereby at the solution flow path output A deionized solution is produced at the end.

In embodiments, the first ions are negatively charged ions and the second ions are positively charged ions, and functionalizing the first plurality of pores includes functionalizing the first edges of the first plurality of pores to have Negatively charged to repel negatively charged ions in the solution, and functionalizing the second plurality of pores includes functionalizing a second edge of the second plurality of pores to have a positive charge to repel positively charged ions in the solution. charged ions. Functionalizing the first edges of the first plurality of pores to have a negative charge may include functionalizing the first edges of the first plurality of pores with oxygen, nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, or iodine. Alternatively, functionalizing the first edge of the first plurality of pores to have a negative charge may comprise functionalizing the first edge with polymer chains or amino acid chains having an overall negative charge. Functionalizing the second edges of the second plurality of pores to have a positive charge may include functionalizing the second edges with boron, hydrogen, lithium, magnesium, or aluminum. Alternatively, functionalizing the second edges of the second plurality of pores to have a positive charge may comprise functionalizing the second edges with polymer chains or amino acid chains having an overall positive charge.

In another embodiment, the first ions are positively charged ions and the second ions are negatively charged ions, and functionalizing the first plurality of pores includes functionalizing a first edge of the first plurality of pores to have a positive charge to repel positively charged ions in the solution, and functionalizing the second pores includes functionalizing a second edge of the second plurality of pores to have a negative charge to repel negatively charged ions in the solution. ion. Functionalizing the second edges of the second plurality of pores to have a negative charge may include functionalizing the second edges with oxygen, nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, or iodine. Alternatively, functionalizing the second edges of the second plurality of pores to have a negative charge may comprise functionalizing the second edges with polymer chains or amino acid chains having an overall negative charge. Functionalizing the first edges of the first plurality of pores to have a positive charge may include functionalizing the first edges with boron, hydrogen, lithium, magnesium, or aluminum. Alternatively, functionalizing the first edge of the first plurality of pores to have a positive charge comprises functionalizing the first edge with polymer chains or amino acid chains having an overall positive charge.

The method may further include sizing a first plurality of pores of the first graphene sheet to repel transport of a first ion, and sizing a second plurality of pores of the second graphene sheet to repel second ions delivery. The method may also include applying a first charge to the first graphene sheet and applying a second charge to the second graphene sheet, wherein the first charge repels the first ion and the second charge repels the second ion.

A deionizer is disclosed comprising: a graphene sheet having a plurality of pores functionalized to repel first ions in solution from being transported through the plurality of pores, the first ions not being transported ions affecting a second ion in the solution from transport through the functionalized plurality of pores; a solution flow path having an input and an output, wherein the graphene sheet is placed between the solution flow path input and between the solution flow path outputs; and a source of ion-laden solution. introducing a solution laden with ions into a solution flow path input end, past the graphene sheet, thereby producing a first ionic solution comprising first ions and second ions on the solution flow path input side of the graphene sheet and deionized solution on the output side of the solution flow path of the graphene sheet.

In an embodiment, the first ion is a negatively charged ion, the second ion is a positively charged ion, and the plurality of pores functionalized includes a plurality of pores with negatively charged edges to repel charged ions in solution. negatively charged ions. In another embodiment, the first ion is a positively charged ion, the second ion is a negatively charged ion, and the plurality of pores functionalized includes a plurality of pores with positively charged edges to repel positively charged ions.

The deionizer may further include a plurality of pores of the graphene sheet sized to resist transport of the first ions. The deionizer may further include charging the graphene sheet with a charge that repels the first ions.

A solution deionizer is disclosed comprising: a first graphene sheet having a first plurality of pores functionalized to repel first ions from transport through the functionalized first a plurality of pores through which non-transported first ions affect second ions in the solution from being transported through the functionalized first plurality of pores; a second graphene sheet having a second plurality of pores , the second plurality of pores are functionalized to repel the second ions in the solution from being transported through the functionalized second plurality of pores, the non-transported second ions affecting the first ions in solution prevent transport through said functionalized second plurality of pores; a solution flow path having an input and an output, wherein said first graphene sheet is downstream of said solution flow path input , and the second graphene sheet is between the first graphene sheet and the solution flow path output; and a source of ion-laden solution. A solution laden with ions is introduced at the input of the solution flow path, through the first graphene sheet, and then through the second graphene sheet, thereby producing a deionized solution at the output of the solution flow path.

In embodiments, the first ions are negatively charged ions, the second ions are positively charged ions, and the functionalized first plurality of pores includes negatively charged edges that repel negatively charged ions in solution The first plurality of pores, and the functionalized second plurality of pores includes a second plurality of pores having positively charged edges that repel positively charged ions in solution. In another embodiment, the first ions are positively charged ions, the second ions are negatively charged ions, and the functionalized first plurality of pores includes positively charged ions that repel positively charged ions in solution. and the functionalized second plurality of pores includes a second plurality of pores having negatively charged edges that repel negatively charged ions in solution.

The solution deionizer may further include a first plurality of pores of the first graphene sheet sized to resist transport of the first ion and a second plurality of pores of the second graphene sheet sized to resist transport of the second ion. pores. The solution deionizer may further include a first graphene sheet with a first charge and a second graphene sheet with a second charge, wherein the first charge repels the first ions and the second charge repels second ion.

Brief description of the drawings

Figure 1 is an abstract cross-sectional illustration of a prior art reverse osmosis (RO) filtration membrane;

2 is an abstract illustration of a water filter using perforated graphene sheets in accordance with an aspect of the present disclosure;

Figure 3 is a plan view of a perforated graphene sheet useful in the arrangement of Figure 2, showing the shape of one of the plurality of pores;

Figure 4 is a plan view of a perforated graphene sheet showing functionalized perforations or pores and their dimensions;

Figure 5 is a plan view of a backing sheet that may be used in conjunction with the perforated graphene sheet of Figure 2;

6 is an abstract illustration of a water deionization filter using a plurality of perforated graphene sheets in accordance with an aspect of the present disclosure; and

Fig. 7 is a simplified diagram showing a piping arrangement generally corresponding to that of Fig. 6, in which perforated graphene sheets are helically wound and packaged in a cylinder.

A detailed description

FIG. 2 is an abstract illustration of a basic deionization apparatus 200 according to an exemplary embodiment or aspect of the disclosure. In FIG. 2 , channels 210 deliver ion-laden water to a filter membrane 212 disposed in a support chamber 214 . The ion-loaded water may be, for example, seawater or brackish water. In an exemplary embodiment, filter membrane 212 may be wound in a helical shape in known manner. Flow momentum or pressure for the ion-laden water flowing through channel 210 of FIG. 2 may be provided by tank 216 by gravity or by pump 218 . Valves 236 and 238 allow selection of a source of ion-laden water. In the device or arrangement 200, the filter membrane 212 is a perforated graphene sheet having perforations (also referred to as pores). Graphene is a monoatomic layer thick layer of carbon atoms bonded together to define a sheet 310 as shown in FIG. 3 . The thickness of a single graphene sheet is about 0.2 nanometers (nm). In practice, the thickness of a single graphene sheet is believed to be about 0.2 nm to 0.3 nm, and specifically about 0.23 nm. Multiple graphene sheets with greater thickness can be formed. The carbon atoms of the graphene sheet 310 of FIG. 3 define a repeating pattern of hexagonal ring structures (benzene rings) composed of 6 carbon atoms that form a honeycomb lattice of carbon atoms. Interstitial apertures 308 are formed by each 6-carbon atom ring structure in the sheet, and the interstitial apertures are less than 1 nanometer across. In practice, the skilled artisan will recognize that interstitial pores are believed to span about 0.23 nanometers in their longest dimension. The size is too small to pass water or ions.

The deionization device of Figure 2 has a solution flow path from a water source 201 or 216 to a channel 210, which can be considered as the input of the solution flow path. From channel 210, the solution flow path extends to the solution flow path input side of chamber 214, then through graphite sheet 212, then to the solution flow path output side of chamber 214, and finally to channel 222, which is considered the solution flow path output of the flow path. Water 201 laden with undesired ions may be pressurized by pump 218 or by gravity feed from tank 216, thereby producing pressurized water. The pressurized water is applied to the first side 212u of the perforated graphene 212 to cause water molecules to flow to the second side 2121 of the perforated graphene sheet.

To form the perforated graphene sheet 212 of FIG. 2 , one or more perforations are made, as shown in FIG. 3 . A typically substantially circular or nominally circular aperture 312 is defined by the graphene sheet 310 . In an embodiment, pores 312 have a nominal diameter of about 2 nanometers. The 2-nanometer size is chosen to allow transport through the pores of the largest ion typically expected to be present in brine or brackish water, which is chloride. In some embodiments, pores 312 may have a nominal diameter of 0.8 nm to 1.2 nm. However, the functionalization of the edges of the pores as detailed herein depends on repelling ions from being transported through the pore, even if the pore is otherwise resized to allow transport of ions. The generally circular shape of the pores 312 is influenced by the fact that the hexagonal carbon ring structure of the graphene sheet 310 partially defines the boundaries of the pores.

Pores 312 may be made by selective oxidation, which means exposure to an oxidizing agent for a selected period of time. It is contemplated that the apertures 312 may also be laser drilled. As described in the publication Nano Lett. 2008, Vol. 8, no. 7, pg 1965-1970, the most straightforward perforation strategy is to treat graphene membranes with oxygen diluted in argon at high temperature. As described therein, through pores or pores ranging from 20 nm to 180 nm were etched in graphene using 350 mTorr of oxygen in 1 atmosphere (atm) of argon at 500° C. for 2 hours. The paper reasonably suggests that the number of pores is related to the defects of the graphene sheet, and that the size of the pores is related to the residence time. It is considered to be the preferred method to create the desired perforations in the graphene structure. The structures can be graphene nanoplates and graphene nanoribbons. Therefore, pores within a desired range can be formed by a shorter oxidation time. Another, more related approach utilizes self-assembled polymers that produce masks suitable for patterning using reactive ion etching. The P(S-block MMA) block copolymer forms an array of PMMA pillars that are reconstructed to form the vias of the RIE. The hole pattern is very dense. The number and size of pores are controlled by the molecular weight of PMMA block (PMMA block) and the weight fraction of PMMA in P (S-MMA). Either method has the potential to produce perforated graphene sheets.

The edges of the pores can be functionalized with specifically charged functional groups. Charged groups around the edges repel similarly charged ions, increasing the activation barrier for similarly charged ions to transport through the pore. In addition, ions of opposite charge can be affected to remain with ions that were not transported. Separation of positive and negative ions would require a large amount of energy input into the system, which is not a feature of the present invention. Thus, by repelling similarly charged ions from transport through the functionalized pores, oppositely charged ions are effectively also repelled from transport through the functionalized pores. In embodiments, the edges of the pores may be functionalized with oxygen, which is a negatively charged ion. Sheets with pores functionalized with oxygen will repel the negatively charged chloride ions, which will cause the chloride ions to be transported through the pores at a very low rate or not at all. Positively charged sodium ions are influenced to remain within chamber 226 along with the repelled chloride ions. In other embodiments, elements other than oxygen can be used to functionalize the edges of the pores with a negative charge. For example, in embodiments, at least one of nitrogen, phosphorous, sulfur, fluorine, chlorine, bromine, and iodine may be used to functionalize the edges along with negative charges.

Thus, if the edges of the pores of sheet 212 are charged to repel ions of one charge, ions of the opposite charge may also be affected and not pass through the sheet. Although it is possible to pass oppositely charged ions through the pores of the sheet by inputting large amounts of energy into the system, it is expected that adding this amount of energy to the system would produce reactions that are undesirable in the case of deionization (e.g., generation of chlorine gas). or hydrogen).

As will be appreciated, in another embodiment the edges may carry positively charged ions such as boron. Sheets with pores functionalized with boron will allow positively charged sodium ions to pass through the pores at a very low rate or not at all. The negatively charged chloride ions will tend to stay with the sodium ions and also pass through the pores at a very low rate or not at all. In other embodiments, elements other than boron can be used to functionalize the edges of the pores with a positive charge. For example, in embodiments, at least one of hydrogen, lithium, magnesium, and aluminum may be used to functionalize the edges along with a positive charge.

In another embodiment, the edges of the pores can be functionalized with polymer chains or amino acid chains having an overall positive charge or an overall negative charge. Some candidate polymers include polyethylene oxide, polysulfonimide-based polymers, gold-thiol interlayers, ruthenium-based organometallic compounds, and electrolytic polymers. The use of polymer chains or amino acid chains may allow greater control of the charge strength on the pore edges, thereby allowing some control over the repulsion and/or attraction of the functionalized pores. The charge strength can be important depending on the type of ions that need to be filtered by the graphene sheet.

Functionalization of the pores can be achieved by a variety of generally known methods. In an embodiment, the graphene sheet can be seeded with a chemical or group that is reactive with oxygen and then exposed to an oxygen plasma, whereby the chemical or group reacts and forms a Functionalized pores are created in the ene sheet, resulting in functionalized pores on the graphene sheet. In another embodiment, chemical functional groups that are responsive to external stimuli, such as electric charge or light pulses, can be rendered functional by applying them to the edges of existing pores and then exposing the sheet to charge or light pulses. connected to this edge, forming a functionalized pore. Acid treatment, reactive ion etching, or standard organic chemistry techniques can also be used to functionalize the edges of the pores. Methods of functionalization include, but are not limited to: reactive ions and molecular species such as carbon tetrafluoride plasma, oxygen plasma, atomic oxygen, nitrogen plasma, and atomic nitrogen. The functionalization of the material after the initial defect in the structure is dependent on the chemical composition remaining on the material: for example, if a nitrogen or oxygen reactive group is attached to the material, the material can react with an organic acid chloride to An ester linkage or an amide linkage occurs between the material and the functional group. The functional group attached to the material can be anything that would support the functionality of the linker.

As stated, the graphene sheet 310 of FIG. 3 has a thickness of only one atom. Therefore, the sheet tends to be flexible. The bending of the graphene sheet can be improved by applying a backing structure to the sheet 212 . The backing structure of the perforated graphene sheet 212 is illustrated as 220 in FIG. 2 . In this embodiment, the backing structure 220 is a sheet of perforated polytetrafluoroethylene (sometimes referred to as polytetrafluoroethylene). The thickness of the backing sheet may be, for example, 1 millimeter (mm).

It should be noted that in the device or arrangement of FIG. 2 , the pressure of the ion-laden water applied through path 210 to perforated membrane 212 may be provided by gravity from tank 216 , thereby emphasizing one of the aspects of device 200 . That is, unlike RO membranes, the perforated graphene sheets 310 ( FIG. 3 ) forming the perforated membranes are hydrophobic, and water passing through the perforated pores ( 312 of FIGS. 2 and 3 ) is not attractive (due to Humidity) hindrance. Furthermore, as noted, the length of the flow path through the pores 312 in the graphene sheet 310 is equal to the thickness of the sheet, which is about 0.2 nm. This length is much smaller than the length of a random path extending through the RO membrane. Therefore, very little pressure is required to provide fluid flow, or conversely, in the perforated graphene sheet 310, the flow at a given pressure is much greater. This in turn translates into low energy requirements for ion separation. It is believed that the pressure required in an RO membrane to move water through the membrane against the osmotic pressure includes a frictional component which causes the membrane to heat up. Therefore, some of the pressure that must be applied to the RO membrane is not used to overcome the osmotic pressure, but instead becomes heat. Simulations showed that the perforated graphene sheets reduced the required pressure by at least a factor of five. Thus, where a RO membrane may require 40 pounds per square foot (PSI) of pressure on the upstream side to achieve a specific flow of deionized water with a specific ion concentration, a perforated graphene sheet may require 8 PSI for the same flow rate the following.

As mentioned, the perforations 312 of the graphene sheet 212 of FIG. 2 (or equivalently the graphene sheet 310 of FIG. 3 ) can be functionalized to effectively block ions of a certain charge from passing through the graphene sheet. As further described, ions of opposite charge to said one charge can also be efficiently blocked, since oppositely charged ions tend to stay together with the blocked one charge ion in the absence of substantial energy input. Therefore, any ions not expected to pass through the graphene sheet may be expected to accumulate in the upstream side 226 of the graphene sheet-support chamber 214 . The accumulation of ions in the upstream "chamber" 226 is referred to herein as a "concentrate" and ultimately reduces the flow of water through the perforated graphene sheet 212, thereby tending to make it less effective for deionization. As shown in FIG. 2 , an additional path 230 is provided along with a drain valve 232 to allow the concentrate to be purged or drained.

The operation of the device or arrangement 200 of Figure 2 may be in a "batch" fashion. The first mode of batch operation occurs with the flow of ion-laden water through path 210, and discharge valve 232 is closed to prevent flow. Ion-laden water fills the upstream side 226 of the support chamber 214 . Water molecules are allowed to flow through the perforated graphene sheet 212 of FIG. 2 and through the backing sheet 220 to the downstream side 227 of the support chamber 214 . Ions (both positively and negatively charged) accumulate on the upstream side 226 and deionized water accumulates on the downstream portion 227 and can be discharged via path 222 to a capture vessel (exemplified as tank 224 ). The flow of water molecules may continue until a threshold level of concentrate has accumulated in the upstream chamber 226 . At this time, upstream ions can be purged through path 230 using discharge valve 232 .

By way of example, the edges of the perforations (pores) 312 in the graphene sheet 212 of FIG. 2 can be functionalized to have a negative charge. This can be achieved by functionalizing the edges with oxygen, nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine or iodine. Alternatively, this can be achieved by functionalizing the edges with polymer chains or amino acid chains with an overall negative charge. Accordingly, any negatively charged ions in the solution will be repelled from passing through the pores 312 and will collect in the upstream chamber 226 . Furthermore, the positively charged ions in solution will be attracted to stay with the negatively charged ions accumulated in the upstream chamber 226 and will not pass through the pores 312 as well. The deionized water will pass through the pores and collect in the downstream chamber 227 . The upstream chamber can be purged of positively and negatively charged ions by the batch process described. In an alternative embodiment, the edges of the perforations (or pores) 312 in the graphene sheet 212 of FIG. 2 may be functionalized to have a positive charge. This can be achieved by functionalizing the edges with boron, hydrogen, lithium, magnesium or aluminum. Alternatively, this can be achieved by functionalizing the edges with polymer chains or amino acid chains with an overall positive charge. Accordingly, any positively charged ions in the solution will be repelled from passing through the pores 312 and will collect in the upstream chamber 226 . Furthermore, the negatively charged ions in solution will be attracted to stay with the positively charged ions accumulated in the upstream chamber 226 and will not pass through the pores 312 as well. The deionized water will pass through the pores and collect in the downstream chamber 227 . The upstream chamber can be purged of positively and negatively charged ions by the batch process described.

In addition to the pores of the graphene sheet being functionalized to attract or repel certain ions, in embodiments the pores may also be sized or sized to not allow passage of ions of a certain size. For example, the graphene sheet 212 may be perforated by pores 312 sized to not allow or prohibit the flow of chloride ions; these pores have a nominal diameter of 1.3nm to 2nm. Therefore, if the size of the defined pores is 1.3nm to 2nm, chloride ions cannot pass through the perforated graphene sheet 212 and stay in the upstream portion or chamber 226 . (Also by functionalization of the edges to repel chloride ions away from the pore). In some embodiments, pores 312 may have a nominal diameter of 0.8 nm to 1.2 nm. Furthermore, the positively charged sodium ions in solution will be affected to stay with the negatively charged chloride ions accumulated in the upstream chamber 226 and will also not pass through the pores 312 . The deionized water will pass through the pores and collect in the downstream chamber 227 . Changing the size of the pores to filter ions in combination with the edges of the functionalized graphene sheets can lead to increased efficiency of the deionization process. A more detailed description of a method and system for deionization using charged graphene sheets with varying pore sizes is disclosed in co-pending U.S. Patent Application No. 12/868,150 (now designated U.S. Patent No. 8,361,321) , which is incorporated herein by reference in its entirety.

In another embodiment, the entire graphene sheet can be charged except for the pores of the graphene sheet which are functionalized to attract or repel certain ions, adding repulsion of similarly charged ions to the sheet. For example, a graphene sheet with pores functionalized with negatively charged ions such as oxygen can also be connected to a voltage source such that negative charges are placed across the sheet. Negatively charged chloride ions are repelled from transport through the negatively charged perforated graphene sheet 212 and reside in the upstream portion or chamber 226 . Furthermore, the positively charged sodium ions in solution will be affected to stay with the negatively charged chloride ions accumulated in the upstream chamber 226 and will also not pass through the pores 312 . The deionized water will pass through the pores and collect in the downstream chamber 227 .

As will be appreciated, the additional approach of promoting ion repulsion using pores of different sizes and charging the graphene sheets can be combined in various ways with the use of functionalized pores. Thus, one embodiment may use functionalized pores and pores of different sizes, while another embodiment may use functionalized pores and charged graphene sheets. Yet another embodiment can use all three approaches simultaneously, ie, functionalization, different pore sizes, and charged graphene sheets.

4 is an illustration of a graphene sheet with a plurality of perforations, such as the perforations of FIG. 3 . The sheet of FIG. 4 defines twenty apertures 312 . In principle, the flow rate is proportional to the pore density. As the pore density increases, the flow through the pores can become "turbulent," which can negatively affect the flow at a given pressure. Furthermore, as the pore density increases, the strength of the underlying graphene sheet may be locally reduced. Such a reduction in strength may in some cases lead to rupture of the membrane. For pores of 0.6 nm, the center-to-center spacing between pores was found to be approximately optimal at a value of 15 nm. In the embodiment of FIG. 4, the edges of the pores 312 are functionalized with oxygen, although as described elsewhere herein, the edges may be charged with other elements or with polymer chains or amino acid chains. Carbons are functionalized adjacent to the oxygens shown.

The pores shown in Figure 4 are functionalized around the edges of the perforations or pores. In the embodiment shown in Figure 4, the edges of the pores are functionalized with oxygen, nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, or iodine, which renders the edges negatively charged. In another embodiment (not shown), the edges of the pores are functionalized with boron, hydrogen, lithium, magnesium, or aluminum, which renders the edges positively charged. Alternatively, polymer chains or amino acid chains can be used to functionalize the edges of the pores, and the charge of the edges depends on the particular polymer or amino acid used.

5 is a simplified diagram of the structure of a backing sheet that may be used with the graphene sheet of FIG. 2 . In Figure 5, the backing sheet 220 is made of filaments 520 of polytetrafluoroethylene (also known as polytetrafluoroethylene), arranged in a rectangular grid and glued or fused at their intersections. As with perforated graphene sheets, for maximum flow, the size of the backing sheet should be as large as possible commensurate with sufficient strength. The spacing between mutually adjacent filaments 520 facing the same direction may be nominally 100 nm, and the filaments may have a nominal diameter of 40 nm. The tensile strength of the graphene sheet is large, so relatively large unsupported areas in the backing sheet should not be a problem.

6 is an abstract illustration of another embodiment or aspect of the present disclosure of a deionization or desalination device 600 (ie, a solution deionizer) in which multiple layers of differently functionalized graphene sheets are used. In FIG. 6, components corresponding to those of FIG. 2 are designated by like reference alphanumerics. Within the support chamber 614 of FIG. 6, upstream and downstream perforated graphene sheets 612a and 612b, respectively, divide the chamber into three volumes or sections, namely, an upstream section or chamber 626a, a downstream section or chamber 627a, and an intermediate section or chamber. 629. As used herein, the terms upstream and downstream are in terms of the flow of water in the device, expressing the relationship of the components of the device relative to other components, from the input channel 210 to the first graphene sheet 612a, and then from the first graphite The ene sheet 612a goes to the second graphene sheet 612b , and from the second graphene sheet to the output channel 222 . Thus, while perforated graphene sheet 612a is upstream relative to downstream graphene sheet 612b , perforated graphene sheet 612a is downstream relative to input channel 210 . Significantly, the term downstream is not intended to necessarily imply a height relationship between components, i.e., although the second graphene sheet 612b may be downstream of the first graphene sheet 612a, this does not necessarily mean that the second graphene sheet 612b is more downstream than the first graphene sheet 612a. A graphene sheet 612a is lower in height, although it could be. As will be appreciated, the device may be pressurized so that downstream components may be downstream in terms of flow, but may be at a higher elevation than upstream components.

Specifically, the solution or water deionizer device of FIG. 6 has a solution flow path from water 201 , from a vessel or container 216 or pump 218 to a channel 210 which may be considered the input of the solution flow path. From channel 210, the solution flow path extends to upstream chamber 626a of chamber 614, through graphene sheet 612a, through intermediate chamber 629, through graphene sheet 612b, then to downstream chamber 627a, and finally to channel 222, which may be considered as The input end of the solution flow path.

Each perforated graphene sheet 612a and 612b is accompanied by a backing sheet. More specifically, perforated graphene sheet 612a is supported by sheet 620a, and perforated graphene sheet 612b is supported by sheet 620b. As noted, graphene is a monoatomic layer thick layer of carbon atoms that bond together to define a sheet 310 , as illustrated in FIG. 3 . As also noted, the bending of graphene sheets can be improved by applying a backing structure to the sheet.

More specifically, in an embodiment, the upstream graphene sheet 612a is functionalized with the negatively charged edges of the pores 612ac to repel chloride ions from passing through the pores. Negatively charged chloride ions may be repelled from passing the negatively charged edge of the graphene sheet 612a, thereby staying in the upstream portion of the chamber 626a. However, as will be appreciated, the presence of repelled chloride ions on the input side of sheet 612a will affect the sodium ions to stay on the input side as well. As noted, the separation of chloride and sodium ions would require significant energy input into the system, which is not a feature of the present invention. Thus, by repelling chloride ions from passing through the graphene sheet, sodium ions are also effectively repelled from passing through the upstream graphene sheet.

There may be situations where some sodium ions may still pass through the pores of the upstream graphene sheet. For example, if the input solution has an excess of sodium ions relative to chloride ions, the excess sodium ions can be attracted by the negative charges on the graphene sheet to pass through the pores. In another example, the input solution may contain a positively charged third ion other than sodium that may be attracted to transport through the pores of the upstream graphene sheet. In these cases it may be desirable to have a second graphene sheet to filter ions. Furthermore, it may be desirable to have a second graphene sheet to ensure higher levels of desalination.

Thus, the embodiment of FIG. 6 includes a downstream graphene sheet 612b that is perforated to have pores 612bs (second pores) and can be positively charged to repel the transport of sodium ions (or any other positively charged ions) through the graphene sheet. 612b. If sodium or other positive ions are able to transport through the sheet 612a into the chamber 629, they may be repelled from being transported through the downstream positively charged perforated graphene sheet 612b, thus staying or accumulating in the middle portion or chamber 629. Furthermore, to the extent that any chloride ions can be transported into chamber 629, those chloride ions may be attracted to stay with the sodium ions in 629 and also not transported through sheet 612b. Thus, water molecules (H ₂ O) at least substantially free of chloride and sodium ions can flow from the middle portion or chamber 629 through the pores 612bs of the perforated graphene sheet 612b and into the downstream portion or chamber 627a, from where water can pass through. Flow path 222 and collection vessel 224 collect deionized water. Water flow path 222 may be considered a water flow path output, and a valve (not shown) may serve as a water flow path output valve on water flow path output 222 . As will be appreciated, an alternative embodiment in which the upstream graphene sheet 612a has positively charged pores and the downstream graphene sheet 612b has negatively charged pores can operate similarly.

Thus, while it is expected that the single graphene sheet deionizer shown in Figure 2 could (if properly "tuned") adequately produce deionized water, the two graphene sheet deionizer shown in Figure 6 provides the ability to meet the highest Additional layer of deionization standard. As will be appreciated, the second graphene sheet may alternatively be functionalized to repel different types of ions. Additionally, systems employing more than two graphene sheets can be used to ensure that different types of ions are filtered and that deionized water meets the highest standards.

As was the case with the deionization arrangement 200 of Figure 2, the device or arrangement 600 of Figure 6 accumulates or concentrates ions during a deionization operation. More specifically, for a water stream laden with chloride and sodium ions, it is expected that the majority of the chloride and sodium ions would be repelled by the upstream graphene sheet 612a, causing the upstream portion or chamber 626a of the device 600 to accumulate chlorine and sodium ions. concentrate. The middle portion or chamber 629 also accumulates some concentration of chloride and sodium ions, although this concentration is expected to be much lower than that accumulated in the upstream chamber. These concentrated ions can be extracted by selective control of purge connections 630a and 630b and their purge valves 632a and 632b, respectively. More specifically, valve 632a can be opened to allow concentrated chloride and sodium ions to flow from the upstream portion or chamber 626a to a collection vessel, illustrated as tank 634a, and valve 632b can be opened to allow concentrated chloride and sodium ions to flow from the intermediate portion. OR chamber 629 flows to a collection vessel, illustrated as tank 634b. Ideally, the purge valve 632a is closed before beginning to purge the midsection or tank 629, thereby maintaining some pressure across the perforated graphene sheet 612a to provide flow of water through the perforated graphene sheet 612a to aid flushing from the midchamber 629 Concentrate rich in sodium ions. Purge valves 632a and 632b are closed prior to deionization. The scavenged and collected concentrated ions may be of economic value for conversion to solid form in the case of sodium or to gaseous form in the case of chlorine. It should be noted that seawater contains significant amounts of beryllium salts, and these salts, if preferentially concentrated, could be valuable to the pharmaceutical industry as catalysts. As will be appreciated, an alternative embodiment in which the upstream graphene sheet 612a is functionalized with the positively charged edges of the aperture 612ac and the downstream graphene sheet 612b is functionalized with the negatively charged edges 612bs can be operated similarly, and large Part of the ions accumulates in the upstream chamber 626 a and a much lower concentration of ions accumulates in the intermediate chamber 629 . Those accumulated ions can be removed as described above.

Figure 6 also illustrates cross flow valves 654a and 654b, which communicate flow path 658 with upstream portion or chamber 626a and flow path 658 with intermediate portion or chamber 629, respectively. Ion-laden unfiltered water 201 may be routed to flow path 658 by opening valve 652 , or deionized water 202 may be provided by tank 224 by operating pump 660 . From pump 660 , deionization flows through check valve 656 to path 658 . Cross flow valves 654a and 654b are opened and closed simultaneously with purge valves 632a and 632b, respectively, thereby helping to purge concentrate from the chamber.

As discussed, in addition to functionalizing the pores of the graphene sheets to repel certain ions, the graphene sheets in the deionizer can also be sized to not allow passage or transport of ions of a certain size. For example, the size of the perforations can be varied to not allow the passage of chloride ions by selecting a pore size of about 1.3 nm to 2 nm. Alternatively, the size of the perforations can be varied to not allow the passage of sodium ions by selecting a pore size of about 1.3 nanometers. Changing the size of the pores to filter ions combined with the pores of functionalized graphene sheets can lead to increased efficiency of the deionization process.

In an embodiment, the size of the perforations on the graphene sheets 612a and 612b differ in size such that one sheet effectively does not allow flow of chlorine laden water and one sheet effectively does not allow flow of sodium laden water. In embodiments that include perforations of different sizes and functionalization of the pores, deionization is achieved through both. By way of illustration, the upstream graphene sheet 612a is perforated by pores 612ac sized to allow or prohibit the flow of chloride ions; these pores have a nominal diameter of 1.3nm to 2nm. Thus, chloride ions cannot pass through the perforated graphene sheet 612a, but remain in the upstream portion or chamber 626a. Sodium ions are also indirectly repelled from flowing through the perforated graphene sheet 612a into the intermediate chamber 629, since the sodium ions will tend to stay with the repelled chloride ions to prevent charge buildup. The downstream perforated graphene sheet 612b is perforated with pores 612bs sized to allow or prohibit the flow of sodium ions; these pores have a nominal diameter of 1.3 nanometers. Water molecules (H ₂ O) free of at least chloride and sodium ions can flow from the middle portion or chamber 629 through the pores 612bs of the perforated graphene sheet 612b and into the downstream portion or chamber 627a, from where they can pass through the pathway 222 and collect Vessel 224 to collect deionized water.

Also as discussed with respect to the deionizer, in addition to functionalizing the pores of the graphene sheets to attract or repel certain ions, an electric charge can be applied to each graphene sheet, increasing the pair of oppositely charged Attraction of ions and repulsion of similarly charged ions. For example, in addition to having functionalized pores, upstream graphene sheet 612a may be negatively charged, causing it to repel chloride ions from passing through pores 612ac. Negatively charged chloride ions stay in the upstream portion or chamber 626a because they are repelled by the functionalized pores 612ac and the negative charge on the sheet 612a. In addition, the positively charged sodium ions will also tend to stay with the chloride ions in the upstream chamber 626a. Although relatively high concentrations of chloride and sodium ions will be repelled (directly or indirectly) by the functionalization and charge of the graphene sheet 612a, as noted for embodiments with only functionalized pores, it is possible , some chlorine, sodium or other ions can still pass through the pores 612ac. If this occurs, the downstream perforated graphene sheet 612b is perforated with apertures 612bs, and in addition to having positively functionalized apertures, the graphene sheet 612b also carries a positive charge. This positive charge repels the transport of sodium ions through the graphene sheet 612b and also indirectly repels the transport of any chloride ions that might reach the intermediate chamber 629 . Water molecules (H ₂ O) (deionized water) free of at least chloride and sodium ions can flow from the middle portion or chamber 629 through the pores 612bs of the perforated graphene sheet 612b and into the downstream portion or chamber 627a, from where The deionized water is collected through path 222 and collection vessel 224 . An alternative embodiment is operated similarly, where a positive charge is applied to the upstream graphene sheet 612a (where the sheet 612a also has positively charged functionalized pores 612ac) and to the downstream graphene sheet 612b (where the sheet 612b also has positively charged functionalized pores 612ac). Negatively charged functionalized pores 612bs) apply a negative charge.

As will be appreciated, additional ion repulsion methods using pores of different sizes and charging the graphene sheets can be combined in various ways with the use of functionalized pores. Thus, one embodiment may use functionalized pores and pores of different sizes, while another embodiment may use functionalized pores and charged graphene sheets. Yet another embodiment can use all three approaches simultaneously, ie, functionalization, different pore sizes, and charged graphene sheets.

7 is a simplified diagram of a deionization arrangement according to an aspect of the present disclosure. Components of FIG. 7 that correspond to components of FIG. 6 are designated with like reference alphanumerics. In FIG. 7, perforated graphene sheets 612a and 612b are rolled or helically wound into a cylindrical form and inserted into a housing (illustrated as 712a and 712b, respectively), as is known in the art of RO membranes.

Those skilled in the art will appreciate that ions other than chlorine and sodium can be removed from water by selective functionalization of pores on a graphene sheet or sheets.

The method for deionizing an aqueous solution comprises the steps of: functionalizing a plurality of pores of a graphene sheet to repel first ions in the solution from being transported through the functionalized plurality of pores, which are not transporting a first ion to affect a second ion in the solution so that it is not transported through the functionalized plurality of pores; placing the graphene sheet between a solution flow path input and a solution flow path output and passing a solution into the solution flow path input end and through the functionalized plurality of pores of the graphene sheet, thereby creating a deionized on the solution flow path output side of the graphene sheet solution and a second solution comprising first ions and second ions on the input side of the solution flow path of the graphene sheet.

The method for deionizing a solution comprises the step of: functionalizing a first plurality of pores of a first graphene sheet to repel first ions in the solution from transport through the functionalized first ions. a plurality of pores, the untransported first ions also affect second ions in the solution from being transported through the functionalized first plurality of pores; making the second plurality of pores of the second graphene sheet one of the pores is functionalized to repel second ions in the solution, the non-transported second ions also affecting the first ions in the solution from being transported through the functionalized second plurality of pores; placing the first graphene sheet downstream of the solution flow path input and placing the second graphene sheet between the first graphene sheet and the solution flow output; and passing solution into the solution flow A path input, through the first graphene sheet, and then through the second graphene sheet, thereby producing a deionized solution at the solution flow path output.

Claims (36)

1. for the method for the deionization of solution, said method comprising the steps of:

Make a plurality of hole functionalization of graphene film with the first ion repelling in described solution, it not transported by described a plurality of holes through functionalization, the second ion that described the first ion not transporting affects in described solution does not transport by described a plurality of holes through functionalization it;

Described graphene film is placed between flow of solution path input terminus and flow of solution path output terminal; And

Make solution enter described flow of solution path input terminus by a plurality of holes through functionalization of described graphene film, be created in thus solution and second solution that comprises described the first ion and the second ion on the input side of the flow of solution path of described graphene film of the deionization on the flow of solution path outgoing side of described graphene film.

2. the method for deionization as claimed in claim 1, wherein:

Described the first ion is electronegative ion;

Described the second ion is positively charged ion; And

Described a plurality of hole functionalization is comprised and make the limbic function of described a plurality of holes to there is negative charge, thereby repel the electronegative ion in described solution.

3. the method for deionization as claimed in claim 2, the limbic function that wherein makes described a plurality of holes comprises with oxygen, nitrogen phosphate and sulfur, fluorine, chlorine, bromine or iodine and makes described limbic function to have negative charge.

4. the method for deionization as claimed in claim 2, the limbic function that wherein makes described a plurality of holes comprises with polymer chain or the amino acid chain with whole negative charge and makes described limbic function to have negative charge.

5. the method for deionization as claimed in claim 1, wherein:

Described the first ion is positively charged ion;

Described the second ion is electronegative ion; And

Described a plurality of hole functionalization is comprised and make the limbic function of described a plurality of holes to there is positive charge, thereby repel the positively charged ion in described solution.

6. the method for deionization as claimed in claim 5, the limbic function that wherein makes described a plurality of holes comprises with boron, hydrogen, lithium, magnesium or aluminium and makes described limbic function to have positive charge.

7. the method for deionization as claimed in claim 5, the limbic function that wherein makes described a plurality of holes comprises with polymer chain or the amino acid chain with overall positive charge and makes described limbic function to have positive charge.

8. the method for deionization as claimed in claim 1, its size that also comprises a plurality of holes that limit described graphene film is to resist transporting of described the first ion.

9. the method for deionization as claimed in claim 1, it also comprises to described graphene film application electric charge, the first ion described in wherein said electrical charge rejection.

10. the method for deionization as claimed in claim 9, its size that also comprises a plurality of holes that limit described graphene film is to resist transporting of described the first ion.

The method of 11. deionizations for solution, said method comprising the steps of:

Make more than first hole functionalization of the first graphene film with the first ion repelling in described solution, it not transported by described more than first hole through functionalization, the second ion that described the first ion not transporting also affects in described solution does not transport by described more than first hole through functionalization it;

Make more than second hole functionalization of the second graphene film with the second ion repelling in described solution, it not transported by described more than second hole through functionalization, the first ion that described the second ion not transporting also affects in described solution does not transport by described more than second hole through functionalization it;

Described the first graphene film is placed in to the downstream of flow of solution path input terminus and described the second graphene film is placed between described the first graphene film and flow of solution output terminal; And

Make solution enter described flow of solution path input terminus, by described the first graphene film, then by described the second graphene film, at described flow of solution path output, produce thus the solution of deionization.

The method of 12. deionizations as claimed in claim 11, wherein:

Described the first ion is electronegative ion;

Described the second ion is positively charged ion;

Described more than first hole functionalization comprised and make the first edge functionalization of described more than first hole to there is negative charge, thereby repel the electronegative ion in described solution; And

Described more than second hole functionalization comprised and make the second edge functionalization of described more than second hole to there is positive charge, thereby repel the positively charged ion in described solution.

13. methods as claimed in claim 12, the first edge functionalization that wherein makes described more than first hole comprises with oxygen, nitrogen phosphate and sulfur, fluorine, chlorine, bromine or iodine and makes described the first edge functionalization to have negative charge.

The method of 14. deionizations as claimed in claim 12, the first edge functionalization that wherein makes described more than first hole comprises with polymer chain or the amino acid chain with whole negative charge and makes described the first edge functionalization to have negative charge.

The method of 15. deionizations as claimed in claim 12, the second edge functionalization that wherein makes described more than second hole comprises with boron, hydrogen, lithium, magnesium or aluminium and makes described the second edge functionalization to have positive charge.

The method of 16. deionizations as claimed in claim 12, the second edge functionalization that wherein makes described more than second hole comprises with polymer chain or the amino acid chain with overall positive charge and makes described the second edge functionalization to have positive charge.

The method of 17. deionizations as claimed in claim 11, wherein:

Described the first ion is positively charged ion;

Described the second ion is electronegative ion;

Described more than first hole functionalization comprised and make the first edge functionalization of described more than first hole to there is positive charge, thereby repel the positively charged ion in described solution; And

Described the second hole functionalization is comprised and make the second edge functionalization of described more than second hole to there is negative charge, thereby repel the electronegative ion in described solution.

The method of 18. deionizations as claimed in claim 17, the second edge functionalization that wherein makes described more than second hole comprises with oxygen, nitrogen phosphate and sulfur, fluorine, chlorine, bromine or iodine and makes described the second edge functionalization to have negative charge.

The method of 19. deionizations as claimed in claim 17, the second edge functionalization that wherein makes described more than second hole comprises with polymer chain or the amino acid chain with whole negative charge and makes described the second edge functionalization to have negative charge.

The method of 20. deionizations as claimed in claim 17, the first edge functionalization that wherein makes described more than first hole comprises with boron, hydrogen, lithium, magnesium or aluminium and makes described the first edge functionalization to have positive charge.

The method of 21. deionizations as claimed in claim 12, the first edge functionalization that wherein makes described more than first hole comprises with polymer chain or the amino acid chain with overall positive charge and makes described the first edge functionalization to have positive charge.

The method of 22. deionizations as claimed in claim 11, its size that also comprises more than first hole that limits described the first graphene film to be to resist transporting of described the first ion, and the size of more than second hole that limits described the second graphene film is to resist transporting of described the second ion.

The method of 23. deionizations as claimed in claim 11, it also comprises to described the first graphene film applies the first electric charge and applies the second electric charge to described the second graphene film, the second ion described in the first ion and described the second electrical charge rejection described in wherein said the first electrical charge rejection.

The method of 24. deionizations as claimed in claim 23, its size that also comprises more than first hole that limits described the first graphene film to be to resist transporting of described the first ion, and the size of more than second hole that limits described the second graphene film is to resist transporting of described the second ion.

25. deionizaters, it comprises:

The graphene film with a plurality of holes, described a plurality of hole does not transport by described a plurality of holes it through functionalization with the first ion repelling in solution, and the second ion that described the first ion not transporting affects in described solution does not transport by described a plurality of holes through functionalization it;

The flow of solution path with input terminus and output terminal, wherein said graphene film is placed between described flow of solution path input terminus and described flow of solution path output terminal; And

Load has the source of the solution of ion;

Wherein described load there is is the solution of ion to introduce described flow of solution path input terminus, through described graphene film, be created in thus the first solion that comprises described the first ion and described the second ion on the flow of solution path input side of described graphene film and the solution of the deionization on the outgoing side of the flow of solution path of described graphene film.

26. deionizaters as claimed in claim 25, wherein:

Described the first ion is electronegative ion;

Described the second ion is positively charged ion; And

Described a plurality of holes through functionalization comprise that a plurality of holes with electronegative edge are to repel the electronegative ion of described solution.

27. deionizaters as claimed in claim 25, wherein:

Described the first ion is positively charged ion;

Described the second ion is electronegative ion; And

Described a plurality of holes through functionalization comprise that a plurality of holes with positively charged edge are to repel the positively charged ion of described solution.

28. deionizaters as claimed in claim 25, the size of a plurality of holes of wherein said graphene film is defined to resist transporting of described the first ion.

29. deionizaters as claimed in claim 25, wherein make described graphene film with electric charge, the first ion described in described electrical charge rejection.

30. deionizaters as claimed in claim 29, the size of a plurality of holes of wherein said graphene film is defined to resist transporting of described the first ion.

31. solution deionizaters, it comprises:

First graphene film with more than first hole, described more than first hole do not transport by described more than first hole through functionalization it through functionalization to repel the first ion, and the second ion that described the first ion not transporting affects in solution does not transport by described more than first hole through functionalization it;

Second graphene film with more than second hole, described more than second hole do not transport by described more than second hole through functionalization it through functionalization with the second ion repelling in described solution, and the first ion that described the second ion not transporting affects in described solution does not transport by described more than second hole through functionalization it;

The flow of solution path with input terminus and output terminal, the downstream of wherein said the first graphene film in described flow of solution path input terminus, and described the second graphene film is between described the first graphene film and described flow of solution path output terminal; And

Load has the source of the solution of ion;

Wherein described load there is is the solution of ion to introduce described flow of solution path input terminus, through described the first graphene film, then pass through described the second graphene film, at described flow of solution path output terminal, produce thus the solution of deionization.

32. solution deionizaters as claimed in claim 31, wherein:

Described the first ion is electronegative ion;

Described the second ion is positively charged ion;

Described more than first hole through functionalization comprises more than first hole with electronegative edge, the electronegative ion described in described electronegative edge exclusion in solution; And

Described more than second hole through functionalization comprises more than second hole with positively charged edge, the positively charged ion described in described positively charged edge exclusion in solution.

33. solution deionizaters as claimed in claim 31, wherein:

Described the first ion is positively charged ion, and described the second ion is electronegative ion,

Wherein said more than first hole through functionalization comprises more than first hole with positively charged edge, the positively charged ion described in described positively charged edge exclusion in solution; And

Wherein said more than second hole through functionalization comprises more than second hole with electronegative edge, the electronegative ion described in described electronegative edge exclusion in solution.

34. solution deionizaters as claimed in claim 31, the size of more than first hole of wherein said the first graphene film is defined to repel transporting of described the first ion, and the size of more than second hole of described the second graphene film is defined to repel transporting of described the second ion.

35. solution deionizaters as claimed in claim 31, wherein said the first graphene film with the first electric charge and described the second graphene film with the second electric charge, the second ion described in the first ion and described the second electrical charge rejection described in described the first electrical charge rejection.

36. solution deionizaters as claimed in claim 35, the size of more than first hole of wherein said the first graphene film is defined to repel transporting of described the first ion, and the size of more than second hole of described the second graphene film is defined to repel transporting of described the second ion.